Small diameter sausages such as frankfurters or the like usually are made using food casings of cellulose. Cellulose food casings or the like customarily are manufactured in long continuous tubular lengths. For handling convenience, these long tubular lengths are gathered into pleats by shirring and are longitudinally compressed by known techniques to obtain a shorter, relatively rigid tubular element known in the industry as a shirred casing stick. The coherency of a shirred stick is derived in part from the shirring operation which forms the casing into generally conical pleats which nest one within another.
During a stuffing operation the stick is loaded onto a stuffing horn and a food emulsion is fed through the horn and into casing which is drawn forward from the stick by the stuffing pressure. It is not uncommon for a shirred stick 50 cm long to contain upwards of 50 meters or more of casing so a large number of individual frankfurters are made with each stick.
Packaging and shipping of shirred sticks present several problems particularly for the type of casing used for frankfurters which generally have a wall thickness of only about 0.025 to about 0.05 mm.
For example, shirred sticks of this casing are relatively fragile in that the nested pleats of casing formed by the shirring operation are easily separated or pulled apart. If the pleats separate, the stick is said to break or lose "coherency". The result is one or more rigid shirred sections connected by loose unshirred sections. Sticks in this condition are not easily loaded onto a stuffing horn and are not at all suitable for automatic stuffing operations wherein the stick is loaded onto a stuffing horn by mechanical means. Accordingly, the packaging for the shirred sticks must be able to minimize stick breakage.
Shirred sticks also are susceptible to damage if made wet. Since stuffing machines frequently are hosed down with water after a stuffing operation, any sticks in the area must be retained in packaging which provides a barrier to water spray and is not itself damaged by water contact.
In commercial practice it generally is customary to package sticks in tight bundles of fifty (50) sticks. Bundling sticks together accomplishes several functions. For example, if the sticks are tight together, there is less likelihood of relative motion between the sticks so the sticks do not rub one against another. Rubbing together of sticks tends to produce undesirable pinhole damage in shirred casing. Also, a tight bundle helps to prevent bowing of individual sticks. Bowing is the result of a number of factors known in the art and is cause for concern because a bowed stick may not load onto a stuffing horn. A tight bundle further tends to reduce the likelihood of stick breakage as long as the bundle remains intact.
Conventional packaging for retaining a stick bundle generally is a carton or box made of corrugated fiberboard (cardboard) or a combination of corrugated fiberboard panels and a stretch or shrink wrap.
Corrugated fiberboard, hereafter "cardboard", has the drawbacks of adding bulk and expense to the packaging materials and unless it is treated, the material is subject to water damage.
Cardboard packaging also presents problems after use. For example, provision must be made for the collection, storage, disposal and possible recycling of such packaging. Also, there currently is a greater awareness of the environmental impact of packaging materials and the consumer demand, in general, is to reduce as much as possible the amount of packaging materials, such as cardboard, which is used.
Shirred sticks are sold in a number of different diameters and lengths. Accordingly, the count, or number of sticks per container may vary depending upon diameter and length. However, the most common count is fifty sticks per container, known in the art as a "caddie". It further is common to package at least four of such caddies together in a cardboard carton for shipment to the customer. In some cases, depending upon the size of the sticks, caddies may be packaged six or eight to a carton.
Thus, it is desirable not only to reduce or eliminate both the quantity of cardboard used for a caddie and the quantity of cardboard used to package the four, six or eight caddies together for shipment to a customer.
Various alternative packaging arrangements have been proposed which eliminates the corrugated fiberboard components of caddies. Such alternatives simply bundle the shirred sticks (usually fifty) together in various configurations using a flexible wrapper, stretch film, shrink film or the like. Typical packages of this sort are disclosed for example in U.S. Pat. Nos. 5,137,153 and 5,228,572. Pending U.S. application Ser. Nos. 08/030,923 filed Mar. 12, 1993 and Ser. No. 08/112,527 filed Aug. 27, 1993 both assigned to the assignee of this application, disclose still further packages formed with a shrink or stretch film.
The use of a stretch or shrink film to bundle shirred sticks of food casings reduces the volume of packaging materials and yet provides an inexpensive package which maintains the integrity of a caddie of food casings. Moreover, if the packaging film is in the form of a bag or the like, sticks of shirred casing which are removed but unused, can be returned to the package for further storage.
The usual complement of fifty sticks most commonly is arranged in a stack which generally is rectangular in cross section. In this respect, the sticks comprising the caddie are arranged in a cardboard container in ten rows of five sticks each piled one on another such as is shown for example in U.S. Pat. No. 3,471,305. Another rectangular cross sectional arrangement is formed by alternate rows of equal number of sticks wherein the rows are offset one from another so that a row above nests between the sticks of the row below. Such an arrangement is shown in U.S. Pat. No. 3,764,351. In still a further rectangular configuration, the stack of fifty sticks is formed using only nine rows wherein a row above nests between sticks of the row below but the number of sticks in each row alternate between six and five.
With any of the above arrangements, the stack is easily formed by piling sticks in a cardboard caddies. In the case of U.S. Pat. No. 3,764,351 which uses a shrink wrap film, the rectangular shape of the caddie is maintained by cardboard end panels.
It has been found that when only a shrink or stretch film is used for caddie packaging (no cardboard end panels) the rectangular stack is unstable. This is because the inward force exerted by the film in tension about each of the four edges of the stack tends to force the sticks toward a circular configuration. Once the sticks along the stack edges are displaced inward, tension is lost and the package becomes flaccid. This destroys the protection offered by bundling the sticks tightly together.
U.S. Pat. Nos. 5,228,572 and 5,137,153 disclose a film wrapped stack of shirred food casings which is more stable than a rectangular configuration. The sticks are stacked so that there are eight edges so the inward force exerted by the wrapper is distributed over a large area. This stack arrangement is obtained using an odd number of rows (n) wherein the middle row (n/2+1/2) contains one less stick than the rows immediately above and below. Thus, the stack in cross section is two sticks short of a regular hexagon so that when wrapped, the shape of the caddie is generally octagonal in cross section. Accordingly, while the stacking arrangement disclosed in U.S. Pat. Nos. 5,228,572 and 5,137,153 has a smaller perimeter and cross sectional area and is more stable than a conventional rectangular caddie, it nevertheless has several drawbacks.
For example, the omission of two sticks at either end of the middle row makes the stack difficult to form. Prior to wrapping, the middle and lower rows can be supported in a trough. However, in this stacking arrangement there is no inherent support, prior to wrapping, for the sticks at the ends of the rows above the middle row. Further, it can be shown that a larger carton is required to contain four such caddies than is required to contain four caddies of a conventional rectangular configuration. Thus, while wrapping the octagonal shape may use less wrapping film material, cardboard containers of larger surface area are required for a carton of four caddies. This is due to the fact that the caddie shape as disclosed in U.S. Pat. Nos. 5,228,572 and 5,137,153 do not nest one with another.